public function listarDisponiveisProfessorSerie($serie, $idProfessor)
{
$sql = "SELECT * FROM periodo p\n JOIN grupo g ON g.grp_periodo = p.prd_id\n WHERE g.grp_professor = " . $idProfessor . " AND g.grp_serie = " . $serie;
$result = $this->retrieve($sql);
$lista = array();
while ($qr = mysqli_fetch_array($result)) {
$per = new Periodo();
$per->setPrd_id($qr["prd_id"]);
$per->setPrd_periodo($qr["prd_periodo"]);
array_push($lista, $per);
}
return $lista;
}